Protractor or spacing instrument.



E. M. LOW. PROTRAGTOB. 0R SPAGING INSTRUMENT.

APPLIGATIONIILED SEPT. 11, 1903.

Patented Apr. 13, 1909.

3 sums-sum 1.

INVENTOR (fimfl 13m W/ TNE SSE 8:

TH! NORRIS PETERS cm, wasnlnci'cu, n. c,

E. M. LOW. PROTRACTOB. 0R smcme INSTRUMENT.

APPLICATION FILED SEPT. 11, 1903.

Patented Apr. 13, 1909, Pg 4 INVENTOR mm' 4L8 W/TNESSES.

THE NORRIS PETERS 00., wnsnmcrau, u. 1:.

E. M. LOW.

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WI TNESSES:

THE NORRIS FEPIRS C0,, wAsmnn-nu, m c

Patentgd Apr. 13, 1909.

nurrnn s r TIES PATENT @FFIQE.

EVERETT M. LOW, OF NEW YORK, N. Y.

PROTRAGTOR OR SEACING INSTRUMENT.

No. races.

T 0 all whom it may concern:

Be it known that I, EVERETT M. Low, a citizen of the United States,residing at New York, Brooklyn, in the county of Kings and State of NewYork, have invented a new and useful Protractor or Spacing Instrument,of which the following is a specification.

The object of my invention is to provide an instrument for the use ofdraftsmen, engineers and others, whereby the circumi'erence of a circlemay be divided into any number of equal parts which might be required inlaying out the teeth oi gear and ratchet wheels and it can also be usedto lay oil degrees and minutes; it thus is adapted to a wide range or"work for which other protractors can not be used. I can also use myimproved protractor for laying of? sines, chords and tangents and fordescribing polygons. I attain these objects by the instrument which ishereinafter fully de scribed and the nature thereof set forth in theclaims.

Referring to the drawings, in which like characters refer to like parts:Figure 1 is a plan view, Fig. 2 is a side elevation oi ig. 1 and Fig. 3is an end view or the bar or ruler 7c, and shows only so much of theinstrument as is necessary to make clear the connection of said rulertherewith. I ig. i is a section on line acr, 1, through the center ofthe instrument. Fig. 5 is a plan of a portion of the instrument, showingthe ruler is, in a position at right angles to that in which it is shownin Fig.1. Ifig. 6 is a side elevation of Fig. 5. Fig. 7 is a plan viewof a modiiied form of the instrument.

In the accompanying drawings, a, is the base plate, which supports andserves as abearing for the rotative parts, I), is a toothed ring orgear, supported by and turning ireely in the base plate a, said gearbeing shown as having its entire periphery cut with teeth of the samepitch.

C, is a gear, supported by and turning freely in the gear 2'), and alsoin the base )late (t, and may be rotated either by itsef or with. thegear I). The gears Z), and c, are held in place by the ring at, securedto the gear c, by the screws (1 and 61 said ring fitting into a recessin base plate a, the gear a and the ring at being raised slightly abovethe bottom of the base plate a, which allows Specification of LettersFatent.

Application filed September 11, 1903.

Patented April 13, 1909.

Serial No. 172,850.

the free rotation of gear 0, and ring d, over any surface on which thebase plate a, rests, said ring cl serving to hold the ge rs b and c, inplace and at the same time allows the free rotation of said gears. Thepawl 72 is attached to base plate a, by'the screw 12 said pawl beingmovable into and out of engagement with the gear I). The gear 0, isshown as having four segments m m m and we, each segment having adiflerent number of teeth in the same arc this is not necessary as theentire periphery may have teeth ol? the same pitch, but by havingseveral segments I increase the number of different combinations thatcan be made *ith the gears i), and c. I have shown only four segmentsbut it is obvious that several more may be used if desired as it is onlynecessary to have in each segment, such a number of teeth as to allow amovement under the control of its pawl, of such a part of a wholerevolution as is an exact divisor oi the number of teeth in the gear I),and also of the number of teeth there would be in the entire peripheryof the gear c, or the same pitch as the teeth oi the segment.

The essential feature of the instrument is the gears b and 0 having adifferent number of teeth in the same arc and adapted to be rotated adistance equal to one or more teeth in the same or different directionswhereby I am enabled to move a ruler attached to the gear 0 the sum orthe difi'erence of the movements of the gears b and c.

The pawls c c c and 0 are attached to the gear I), by screws 0, 0 c andc, said pawls being movable into and out of engagement with theircorresponding segments on the gear 0; as many pawls being necessary asthere are segments having teeth of different pitches.

lhe sizes of the teeth in the diil'erent segments of gear 0, areexaggerated in order to show the difference more clearly. It isimmaterialwhether the gear I), as shown has its entire periphery cutwith teeth of the same pitch and the gear 0, has several segments, orthe gear I), has several segments and the gear 0, has its entireperiphery cut with teeth of the same pitch.

Each of the segments m m m, and of, must have such a number of teeth asto allow the gear 0, to move such a fractional p art of a revolutionwithout getting beyond the range of its corresponding pawl, that thedenominator of the fraction will be an exact divisor of the number ofteeth in the gear I), and also of the number of teeth there would be inthe gear 0, if its entire periphery were cut with teeth of the samepitch as the segment. if the gear I) has 180 teeth and the segment m ongear 0 has teeth of such a pitch that the entire circumference wouldhave 200 teeth, it is only necessary for the segment m to have asufficient number of teeth to allow a movement of the gear 0, equal toone tenth of a revolution, for ten is a common divisor of 180, thenumber of teeth in the gear I), and of 200 the number of teeth the geara, would have if its entire circumference had teeth of the same pitch asthe segment m The segment we may have teeth of such a pitch that the,entire circumference of gear 0 would have 192 teeth then the segmentwould require such a number of teeth as to allow a movement of the gear0, equal to one twelfth of a revolution, or any other fractional part,the denominator of which fraction is a common divisor of 180 the numberof teeth in the gear I) and 192 the number of teeth in the wholecircumference of the gear a if of the same itch as the teeth in thesegment m Simiarly the segment m may have teeth of such a pitch thatthere would be 189 teeth in the entire circumference of the gear 0 inwhich case we may have a movement of one ninth of a revolution. Thesegment m may have teeth of such a pitch that there would be 165 teethin the entire circumference of the gear 0, when a movement of one1ifthor one fifteenth may be use The gear 0, has a bar or ruler f across it,the edge of which is on a line with the center of the gear, said rulerhaving a mark f midway of its length, by which the center of theinstrument can be brought to the center it is desired to work from; theother half of the space inside the rim of the gear 0, is open, giving aclear view of the drawing or other surface under the instrument, thisallowing a line to be drawn through or from the center.

The arm g is secured to the gear 0, by the screws and g and extendsbeyond the base plate a; adapted to slide onto the arm g is the ead h,which has two dovetailed slots h and Its at right angles to each other.The bar or ruler k, is fitted to slide in the dovetailed slot 76 111 thehead 7L, and by means of the two dovetailed slots h, and 7&5 in the headit, which fit the arm 9, the head h, can be placed on the arm g, bymeans of the slot 7L in such a position as to bring the ruler 7c, in theposition shown in Figs. 1, 2, and 3; or by means of the slot M, the head7L, can be placed on the arm g, so as to bring the ruler 7c, in theposition shown in Figs. 5, and 6. The screw 72 serves to clamp the rulerk, to the head it, and the head it to the arm 9, whichever position thehead occupies on the arm 9. The ruler 7c is movable endwise in the headh, and the head it is also movable lengthwise on the arm g. The rulermay be used as shown in Fig. 1 when working on the outside of the baseplate a, or it may be used as shown in Fig. 5, when it is desired todraw sines, tangents, chords or polygons, when working on the inside ofthe instrument, the head it, and ruler 7c, may be removed and the rulerf, is used, the working edge of both rulers being on a line through thecenter of the instrument, and the edge of the rulers being bereled asshown on ruler 7c in Fig. 3.

In using my improved protractor I may by using the gear I) only, getnumber of different divisions, if the gear I), has 180 teeth I candivide a circle into any number of parts that is contained in 186. Byusing the gear I), having 180 teeth and the segment m, on gear 0 having20 teeth in an arc of one-tenth which would be equivalent to 200 teethin its whole circumference. I may by moving the gear 5, and with it thegear 6, forward or clockwise, a distance of one tooth and then movingthe gear 0, backward a distance of one tooth on segment m get a divisionrepresented by the difference between one-one hundred and eightieth andone-two hundredth of a revolution which is one-eighteen hundredth of thecircumference of a circle or twelve minutes, and the rulers f, and It,would move over that are. T his operation maybe repeated until we havereached the limit of the teeth in the segment, when the gear 7), isturned backward one-tenth of a revolution and the gear 0, is turnedforward one-tenth of a revolution when the edge of rulers f, and 76,will coincide with the last division made and we proceed as before.Turning the gear 6, forward two teetn and the gear 0, backward one toothon segment m gives a division of one-three hundredth. Three teethforward on the gear i2, and two teeth backward on the segment m of thegear 0, gives a division of one-one hundred and fiftieth. Two teethforward on the segment m of the gear 0, and one tooth backward on thegear I), gives a division of onetwo hundred and 'wenty-fifth. In asimilar manner by combining different numbers of teeth on the gear 6,and the segment m, on the gear 0, a number of other divisions ma beobtained that are multiples of numbe that are common divisors of 180 and00. if it is desired to divide a circle into 50 equal parts, a movementof four teeth on the segment m would equal one-fiftieth of thecircumference and after repeating the movements of four teeth at a timeuntil we have reached the limit of the teeth in the segment, it isnecessary to turn the gear 0, backward one-tenth of a revolution or 20teeth on the segment m and then turn the gear 5), forstrument.

ward one-tenth of a revolution or 18 teeth when the rulers and is, willcoincide with the last division made, and we proceed as before. Onetooth forward on the gear I), ha ing 180 teeth and one toothbackward onthe segment m on the gear 0, having 16 teeth in an arc of one-twelfthwhich would be equivalent to 19-! teeth on its whole circumference wouldgive a division represented by the difference between one-one hundredand eightieth and one-one hundred and ninety-secondth which isone-twenty-eight hundred and eightieth of the circumference or oneeighthof one degree. Other divisions may be obtained in the manner beforedescribed that are multiples of numbers that are common divisors of 180and 192. The segment m of the gear 0, having 21 teeth in an arc ofone-ninth, which would be equivalent to 189 teeth on the wholecircumference can be used in combination with. the gear I), to obtaindivisions that are multiples of numbers that are common divisors of 180and 189. The segment m of the gear 0, having 11 teeth in an arc ofone-fifteenth which would be equivalent to 165 teeth 011 the wholecircumference can be used in combination with the gear I), to obtaindivisions that are multiples of numbers that are common divisors of 180and 165. The pawl b serves to determine the movement and to locate andretain the gear 6 in position and the pawls c c c and c serve the samepurpose for the gear 0, only one pawl being used at a time on the gear0, and that being the one which corresponds with the teeth of thesegment being used.

The manner of using my improved protractor is as follows: Place thecenter mark f on the rulerf, on the center of the circle to be divided;if the circle is a small one the ruler f, is to be used and thedivisions are made on the inside of the gear 0; if the circle is a largeone the ruler k, is to be used and the divisions are made on the outsideof the in- In Fig. 1 of the drawing the gear 1), is shown as locked byits pawl b the gear 0, is shown with the pawl c interlocked with theteeth of the segment m. To divide a circle into equal divisions ofone-eighth of one degree, release the gear I), and turn it forward orclockwise a distance of one tooth and then lock it with pawl 5 The gear0, has moved forward with the gear 1) moving the ruler f and it forwardone-one hundred and eightieth of a revolution, now release the gear 0,by throwing the pawl 0 out of engagement with the segment m and turn thegear 0, backward one tooth and again lock with the pawl 0 The rulers fand 7c have moved forward one-one hundred and eightieth and backwardone-one hundred and ninety-second of a revolution making the actualforward movement of the rulers f and 7c equal to thediiference betweenone-one hundred and eightieth and one-one hundred and ninety-second orone-twenty-eight hundred and eightieth of a revolution or oneeighth partof one degree. T his operation is repeated until we have turned the gear12 forward and the gear 0 backward any number of teeth within the limitof the segment m it is now necessary to place the gear 0 in such aposition that the hereinbefore described operation may be repeated whichis done by turning the gear 0, forward 16 teeth or onetwelfth of arevolution and the gear I), back ward 15 teeth or one-twelfth of arevolution or any other part of a revolution may be used which is withinthe limit of the segment, which part of a revolution is represented by afraction whose numerator is one and whose denominator is contained awhole number of times in 180 and 192. The gears l) and 0 will now be inthe first described position with reference to their pawls but therulers f, and 70, will have advanced a distance around the circle equalto one-twenty-eight hundred and eightieth multiplied by the number ofmovements of the gear 1) forward and the gear 0 backward. This operationis repeated until the whole or any desired part of the circle isdivided.

In practice it would be preferable to have the teeth of the gears b, andc, numbered, as the numbers would facilitate the use of the instrument,but are not absolutely essential to its use. The ruler is, is movable inthe head it, and the head 71- is also movable on the bar g, and theruler may be used as shown in Fig. 1 when working at a great distancefrom the center or it may be placed on the bar g, in the position shownin Fig. 5 when it is desired to draw tangents or chords or lay outpolygons; when working on small work this head it, and ruler is, may beremoved and the ruler f, used on the inside of the gear 0.

In Fig. 7 I have shown a modified form of the instrument in which thegear c, which corresponds in position to the gear bin Figs. 1 to 6, hasits rim divided into segments, while the gear w, which corresponds inposition to the gear a, in Figs. 1 to 6, has its entire periphery cutwith teeth of the same pitch. This arrangement necessitates acorresponding change in the location of the pawls from that shown inFig. 1, four of the pawls which are for engagement with the teeth of thesegments of the gear 1), being attached tothe base plate, and the onewhich is for engagement with the teeth of the gear 20, being attached tothe gear '0.

I have for convenience shown the gear w, as having 120 teeth and each ofthe four segments of the gear '1), as having teeth of such a pitch, thatthe teeth of each segment differs from the teeth of the other segmentand from the teeth of the gear '11), in the number of teeth in the samearc. The size of the teeth are exaggerated the more clearly to show thatsuch diiierence is intended. I have shown the teeth of the gear o, andw, as having numbers to more easily determine the desired amount ofmovement of the said gears.

Having thus described my invention, what I claim and desire to secure byLetters Patent, is

1. In a protractor or spacing instrument, a supporting plate, a gearadapted to be rotated in said plate, a gear adapted to be rotated in theaforesaid plate and gear, the said gears having a different number ofteeth in the same number of degrees of are, an arm adapted. to berotated around a central point, with one or both of said gears and meansfor securing said gears and said arm in the desired position.

2. In a protractor or spacing instrument, a supporting plate, a gearadapted to be rotated in said plate, a concentric gear having a rulersecured thereto, said gears having a diflerent number of teeth in thesame number of degrees of are and adapted to be rotated one or moreteeth in the same or opposite directions whereby the gear having theruler attached is given a'rotative motion. equal to the sum ordifference of the movements of the gears and means for securing saidgears in the desired position for the purpose described. I 3. In aprotractor or spacing instrument, two concentric rings, a ruler securedto one of said rings, the ruler being adapted to a rotative movement, ineither direction, with one or both of said rings, and means forpreventing the movement of said rings as described.

4. In a protractor or spacing instriunent, the combination of asupporting plate a, a gear I), adapted to be rotated in said plate, apawl adapted to be moved into and out oi engagement with the teeth ol'said gear, a gear 0, having a ruler forming a part thereof, said gear 0,being adapted to be rotated in the plate a, and the gear Z), and a pawlattached to the gear 5, and adapted to be moved into and out ofengagement with the teeth of the gear 0, substantially as described.

5. In a protractor or spacing instrument, the combination of twoconcentric toothed rings and a ruler secured to one of said rings therim of one of said rings being divided into segn'icnts, said segmentsdiffering from each other in having a different number of teeth in thesame number of degrees of are; said toothed rings being capable of arotative movement in either direction, whereby the ruler may oe moved apredetermined distance, and means for securing said. rings and saidruler in the desired position for the purpose described.

6. In a protractor or spacing instrument, the combination of thesupportmg plate a,

the gear I), and the gear 0, the gear 0, having its rim divided into twoor more segments; the teeth of the gear I), and the teeth of thesegments of the gear 0, differing in the number of teeth in the samenumber of degrees of arc, and pawls having teeth corresponding to theteeth of the gear I), and the teeth of the segments of the gear 0, forthe purpose described.

7. In a protractor or spacing instrument, the combination of thesupporting plate a, the gear I), the pawl 5 adapted to be moved into andout of engagement with the teeth of the gear 6, the gear 0, having itsrim divided into two or more segments, the segments having a differentnumber oi teeth in the same are, and two or more pawls attached to thegear I), and adapted to be moved into and out of engagement with theteeth of the seg ments of the gear 0.

S. In a protractor or spacing instrument, the combination of the platea, the gear 6, the pawl b the gear 0, having the segments m m m and m,said segments diiiering from each other in the number of teeth in thesame are and the pawls c c c and 0 said pawls being adapted to be movedinto and out of engagement with the teeth of the segments of the gear 0,as an d for the purpose de scribed.

9. In a device of the class described, two concentric toothed rings, oneof said rings having its rim divided. into segments having a diiierentnumber of teeth in the same number of degrees of arc, and an arm adaptedto be moved around a central point a series oi predetermined. distancescorresponding to one or more teeth of either of the said rings and pawlsadapted to engage the teeth of said rings for securing the said arm inthe desired position.

10. In a device of the class described the gear Z) and the gear 0; thegear 0 having its rim divided into segments, the teeth of the gear I)and the teeth of the segments of the gear 0 difiering in the number ofteeth in the same number of degrees of are, and an arm adapted to bemoved around a central point a series of predetermined distancescorresponding to the sum or the difference of one or more teeth of thegear 6 and one or more teeth of one of the segments of the gear 0,

z and paWls adapted to engage the teeth of the said gears for securingthe said arm in the desired position.

11. In a protractor or spacing instrument, the combination of the piatea, the gear 6, the pawl 5 the gear 0, the pawls c c 0*, and 0 the rulerf, the arm g, the head h, the ruler 7c, and the screw it as and for thepurpose described.

12. In a device of the class described, a toothed ring divided intosegments having a different number of teeth in the same number 01'degrees of are and an arm adapted to In testimony whereof I have signedmy be moved around a central polnt a series of name to th1sspecification 1.11 the presence of predetermined distances, the salddlstances two subscribing Witnesses.

corresponding to one or more teeth of one of EVERETT M. LOWV. 5 thesegments of said gear and paWls adapted j Witnesses:

to engage the teeth of said segments for se- 1 WM. H. WOOD,

curing the said arm in the desired position. JAMEs H. WOOD.

